`QVariant::convert` may lead to crash or produce garbage data when
attempting to convert a gadget between a pointer type and a value type,
for example from a variant holding a QLocale gadget to a QLocale*
pointer and vice versa. Similarly, `QVariant::view` may crash under the
same conditions.
The reason is that conversion is implemented through copy construction
assuming that both source and target types are either both pointers or
both values. If converting from pointer to value type, the result is
crash during destruction of the QVariant. If converting from value to
pointer type, the result is a QVariant holding a pointer to garbage
data (and possibly crash if pointer is dereferenced).
Similarly, if attempting to convert a pointer to a QObject derived type
to its value type, the system crashes, with a slightly different failure
mode. During `QVariant::convert`, a temporary `QVariant` of the target
type is created. Since objects that can not be copy constructed are
invalid for `QVariant`, the temporary is left empty without constructing
the target value. Then, when attempting to convert from a pointer type
to a value type, the temporary's destructor is incorrectly called on the
owned object. Since the owned object is never constructed, this leads to
a crash.
The proposed fix is to return false from `QMetaType::view`,
`QMetaType::canView`, `QMetaType::convert`, and `QMetaType::canConvert`
if the target type is of different 'pointedness' than the source type.
After this fix, converting and viewing gadgets and QObjects behaves the
same way as primitive types and core types, which already returned false
when converting between value type and pointer type.
Fixes: QTBUG-114797
Pick-to: 6.5 6.6
Change-Id: If5ad764a60f2f3c912070198073b28999d995f17
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
If we have a rvalue reference to an unshared QVariant, we can avoid
potentially expensive copies, and use move semantics instead.
[ChangeLog][QtCore][QVariant] Added rvalue QVariant overloads of qvariant_cast<T>() and QVariant::value<T>().
[ChangeLog][Potentially Source-Incompatible Changes][QVariant] It is no
longer possible to take the address of a specialization of
qvariant_cast; consider using a lambda function instead.
Change-Id: Ifc74991eadcc31387b755c45484224a3200bb0ba
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Extract Method fromStdVariantImpl() to share the otherwise
more-or-less identical implementation between the two overloads.
Don't use a constrained template version of fromStdVariantImpl() as
fromStdVariant(), because the constraint would have to be very complex
to continue allowing subclasses of std::variant to be passed.
As a drive-by, mark the valueless_by_exception() path Q_UNLIKELY.
[ChangeLog][QtCore][QVariant] Added overload of fromStdVariant()
taking rvalue std::variant<>s.
Fixes: QTBUG-114134
Change-Id: Ia1c7ae93ab421e6689dc9f2d8d0c2295b23cbbf6
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
When passing an rvalue-reference to QVariant, there is no reason to make
a copy if the type is moveable. Moreover, we know that the pointer which
we construct from the object passed to fromValue non-null. We make use
of both facts by parametrizing custom_construct on
non-nullness and availability of a move-ctor, and then dispatching to
the suitable template.
We need to keep the const T& overload, as otherwise code which
explicitly specializes fromValue and passes a const lvalue to it would
stop to compile.
[ChangeLog][QtCore][QVariant] Added fromValue() overload taking rvalues.
Change-Id: I44fb757d516ef364fe7967bc103b3f98278b4919
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
[ChangeLog][QtCore][QVariant] Implemented in-place construction for
QVariant. The constructor taking std::in_place_type<Type> constructs
an object of type Type directly inside QVariant's storage, without any
further copy or move operations. QVariant::emplace() does the same
when replacing the content of an existing QVariant and tries to reuse
previously-allocated memory.
Fixes: QTBUG-112187
Change-Id: I16614ad701fa3bb583976ed2001bb312f119a51f
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
In Qt >= 6.1, < 6.5, a trivially constructible type would have the
NeedsDestruction flag set, but it's dtor pointer would have been null.
In Qt 6.5, the meaning of the NeedsDestruction flag was changed to be
more aligned with what the name suggests, and thus would only be set for
non-trivially destructible types. For QMetaType this was fine, but
QVariant has a check for acceptable metatypes which attempts to verify
whether a QMetaType is usable for QVariant. The check assumes the
semantics of Qt 6.5, and thus fails for metatypes created by older Qt
versions.
To fix this issue, we increment the QMetaType revision field, and only
check the metatype's destruction support if the revision is high enough.
In theory, that allows passing unsuitable metatypes from older Qt
versions to QVariant; however, such code would have been broken in prior
Qt releases already (which didn't attempt the check), and no code that
used to work in any released Qt version will break (as we simply skip a
check that was passing before).
Fixes: QTBUG-113227
Pick-to: 6.5
Change-Id: I12e02bd97d2c410ea1a36efb0ce2389f21d50a30
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
This avoids constructing an object just to copy (later: move) it into a
QVariant.
ChangeLog will be in a follow-up change adding emplace support.
Task-number: QTBUG-112187
Change-Id: I444e580c7d8927d41b3d21d5a521e7c475119e4c
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
A null QString used to make a QVariant containing it null in Qt 5, but
this is no longer the case. Add a test that get_if works as expected.
Task-number: QTBUG-111598
Change-Id: I0f3511e1b33f4a9d67755269455680feda22ddca
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This second patch of the series implements get().
Unlike other get() implementations in Qt, don't use my trick with the
constrained friend free function here. Instead, provide the four
overloads manually, like mandated by the standard library for
std::variant (and, indeed, tuple), such that these functions can also
be used on subclasses of QVariant.
[ChangeLog][QtCore][QVariant] Implemented the type-based std::variant
access protocol (get<T>()/get_if<T>()) to allow easier access to the
contained element than the previous solution of casting data(), as
well as to allow generic code to treat QVariant and std::variant the
same. The holds_alternative<T>() function is not provided, since it's
the same as get_if<T> != nullptr. The index-based variant access
functions (get<I>()/get_if<I>()) are also not provided, because,
unlike std::variant, QVariant does not have a bounded number of
alternative types, and QMetaType IDs are not (all) compile-time
constants.
Fixes: QTBUG-111598
Change-Id: Id7bc41f7d91761b3483ec5604f1a4685c8079844
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
QVariant supports non-default-constructible payloads, in principle
(QTBUG-105140). And fromValue() works with such types, but value()
insists on providing a wide contract and therefore accidentally
requires default-constructible.
We can now invent other "Qt-ish" API like optional::value_or() or a
value() that returns optional<T>, but we should first get the
interface in that generic code must use, and which at the same time is
the most versatile, because it gives write access to the element
stored in the variant: [variant.get], consisting of get_if(), get(),
and holds_alternative(). The latter is the same as get_if() !=
nullptr, so we won't provide it.
This first patch implements get_if(), adds test for it.
As a Hidden Friend supposed to be called with explicit template
arguments, we run into the problem that wg21.link/P0846 solved for
C++20. Add the usual work-around, and check it works.
The ChangeLog will be on the last patch.
Task-number: QTBUG-111598
Change-Id: I23f57ea2de3946944810c5552c68a7a3060a44f2
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
I must have broken this in the 6.5 work I did for QMetaType and
QVariant, but I haven't searched which commit exactly did it. Our
QVariant tests are old and thus only checked the type ID, which meant
that they caused the registration by the act of asking for the ID in the
first place; this commit adds a couple of explicit checks for the type
registered by name before the ID.
Fixes: QTBUG-112205
Pick-to: 6.5 6.5.0
Change-Id: Idd5e1bb52be047d7b4fffffd174f1b14d90fd7a3
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
250ca8d5f8 changed the qConvertToNumber
to have a std::optional return instead of a boolean out-argument.
In doing so a code path that was supposed to report a failure (string
could not be converted to an integer) accidentally starting reporting
success (and converting the string to 0).
The problem is that the `ok` check from QString::toLongLong was
accidentally dropped in the refactoring; previously the function set
`ok` to false and returned 0, now the function just returns 0.
Instead, amend that return to return nullopt (because the conversion has
failed).
Change-Id: Iaedef5463f3ec500a97bd4c9bbddf977f66df61a
Pick-to: 6.5 6.5.0
Fixes: QTBUG-111867
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
A QVariant(QString) was not convertible to an enum not registered with
Q_ENUM() which worked fine in Qt5.
The same problem exists for QVariant(enum) to QString.
Fix it by not bailing out when no metatype for the enum was found and
try to convert it to a qlonglong instead (which is then correctly
converted to the enum type).
Fixes: QTBUG-109744
Pick-to: 6.5 6.4
Change-Id: Ie7bb016a860455b69508f0f46b36474c9c294f3a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This saves (mostly in corelib/time/) some complications that used to
arise from needing different code-paths for different time-specs.
Task-number: QTBUG-108199
Change-Id: I5dbd09859fce7599f1ba761f8a0bfc4633d0bef9
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Put core includes all in a common form, sort alphabetically.
Remove a stray blank line.
Change-Id: I211c6b407f5e49d907cb065521883567f1dd30f4
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Most of them were easy to change. The pair one was a bit of a stretch,
but still worked. I've removed the lines on QPair, since QPair is
std::pair in Qt 6.
Change-Id: I3d74c753055744deb8acfffd17246ec98c583d08
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
qIsNumericType does not return true for enum types, which meant we never
called numericCompare() or numericEquals() when one of the types was an
enum.
Task-number: QTBUG-108188
Change-Id: I3d74c753055744deb8acfffd172449c68af19367
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
The code implementing the C++ rules of type promotion and conversion
was too pedantic. There's no need to follow the letter of the standard,
not when we can now assume that everything is two's complement (this was
true for all architectures we supported when I wrote this code in 2014,
but wasn't required by the standard).
So we can reduce this to fewer comparisons and fewer rules, using the
size of the type, not just the type ID.
Change-Id: I3d74c753055744deb8acfffd172446b02444c0c0
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
This is a semantic patch using ClangTidyTransformator as in
qtbase/df9d882d41b741fef7c5beeddb0abe9d904443d8, but extended to
handle typedefs and accesses through pointers, too:
const std::string o = "object";
auto hasTypeIgnoringPointer = [](auto type) { return anyOf(hasType(type), hasType(pointsTo(type))); };
auto derivedFromAnyOfClasses = [&](ArrayRef<StringRef> classes) {
auto exprOfDeclaredType = [&](auto decl) {
return expr(hasTypeIgnoringPointer(hasUnqualifiedDesugaredType(recordType(hasDeclaration(decl))))).bind(o);
};
return exprOfDeclaredType(cxxRecordDecl(isSameOrDerivedFrom(hasAnyName(classes))));
};
auto renameMethod = [&] (ArrayRef<StringRef> classes,
StringRef from, StringRef to) {
return makeRule(cxxMemberCallExpr(on(derivedFromAnyOfClasses(classes)),
callee(cxxMethodDecl(hasName(from), parameterCountIs(0)))),
changeTo(cat(access(o, cat(to)), "()")),
cat("use '", to, "' instead of '", from, "'"));
};
renameMethod(<classes>, "count", "size");
renameMethod(<classes>, "length", "size");
except that the on() matcher has been replaced by one that doesn't
ignoreParens().
a.k.a qt-port-to-std-compatible-api V5 with config Scope: 'Container'.
Added two NOLINTNEXTLINEs in tst_qbitarray and tst_qcontiguouscache,
to avoid porting calls that explicitly test count().
Change-Id: Icfb8808c2ff4a30187e9935a51cad26987451c22
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Various places were knowingly provoking warnings without telling QTest
to check for and suppress those warnings. Some others did check for
this warning, so let's consistently suppress the noise.
Change-Id: I71b9829680c7a513f4d8fbb3c57442875a6c2dc4
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
We've been requiring C++17 since Qt 6.0, and our qAsConst use finally
starts to bother us (QTBUG-99313), so time to port away from it
now.
Since qAsConst has exactly the same semantics as std::as_const (down
to rvalue treatment, constexpr'ness and noexcept'ness), there's really
nothing more to it than a global search-and-replace, with manual
unstaging of the actual definition and documentation in dist/,
src/corelib/doc/ and src/corelib/global/.
Task-number: QTBUG-99313
Change-Id: I4c7114444a325ad4e62d0fcbfd347d2bbfb21541
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
There were simply two copies of the same row-adding code.
Change-Id: I12240dedf2649c314ad32984f4de9d6b9bf280d8
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
The doc of QMetaEnum::valueToKey() says to use ::valueToKeys() instead
for flag types.
Pick-to: 6.4
Change-Id: I48e5ba47324137f2ce2710f1d876e93e7c562e9f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Since Qt 6.0, QMetaType stores the name obtained from the C++ compiler,
which means we know a type like Qt::Alignment by its proper, full name
of QFlags<Qt::AlignmentFlag>. However, the meta object records only the
bare name of the enumeration, not the full flags.
Pick-to: 6.2 6.3 6.4
Fixes: QTBUG-105932
Fixes: QTBUG-96185
Change-Id: Ic6547f8247454b47baa8fffd170eab977e306377
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
The new name describes the behavior in a better way.
[ChangeLog][Build System] The QT_DISABLE_DEPRECATED_BEFORE macro is
renamed to QT_DISABLE_DEPRECATED_UP_TO. The old name is deprecated, but
is still recognized if it is defined during configuration and the new
name is not defined.
Task-number: QTBUG-104944
Change-Id: Ifc34323e0bbd9e3dc2f86c3e80d4d0940ebccbb8
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
CMakeLists.txt and .cmake files of significant size
(more than 2 lines according to our check in tst_license.pl)
now have the copyright and license header.
Existing copyright statements remain intact
Task-number: QTBUG-88621
Change-Id: I3b98cdc55ead806ec81ce09af9271f9b95af97fa
Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
In one of the three calls to customConstruct() -- QVariant::detach() --
we've already checked that the type is valid, so don't re-emit the
warning there.
Change-Id: I3859764fed084846bcb0fffd1703a3c7c0fb3164
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
So long as you only ask us to copy it. Copying is mandatory, though.
I'll firm up the warning in a later commit, which may not get cherry-
picked as far back.
Pick-to: 6.2 6.3 6.4
Fixes: QTBUG-105140
Change-Id: I3859764fed084846bcb0fffd170432abf65dc197
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
If the metatype does not support copy and default construction, then it
it unsuitunsuitable for use in QMetaType. We cannot prevent users from
passing in such metatypes (as we have e.g. a ctor taking QMetaType), so
verify this in customConstruct, and make the variant invalid in that
case.
Pick-to: 6.2 6.3 6.4
Change-Id: Ib1f0149c8fb9a1cce0049fd0311980754cc85d1b
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Replace the current license disclaimer in files by
a SPDX-License-Identifier.
Files that have to be modified by hand are modified.
License files are organized under LICENSES directory.
Task-number: QTBUG-67283
Change-Id: Id880c92784c40f3bbde861c0d93f58151c18b9f1
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
Multiple tests use qt_internal_add_resource that copies the
functionality that is already implemented inside the
qt_internal_add_test function. Simplify these test by replacing
the qt_internal_add_resource call with the new BUILTIN_TESTDATA
option.
Change-Id: I18475b817d6f87264f0de53817d6c26c5ccab4e2
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
The source was already protected, but the destination wasn't.
Pick-to: 6.2
Change-Id: I300f19c3e65abd8bc1eef4309aefa11852d1c049
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
tst_qvariant.cpp:3624:15: warning: ‘void* memcpy(void*, const void*, size_t)’ writing to an object of type ‘class QVariant’ with no trivial copy-assignment; use copy-assignment or copy-initialization instead [-Wclass-memaccess]
Change-Id: Ic17a33f599b844d8ab5dfffd16aafcbd74823696
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
This header is a C++17 feature that is already used unconditionally
in qtypeinfo.h.
Change-Id: I26330d298e95102f3e94c0c69fc95c1025666eb4
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Qt requires a compiler that support C++17 thus __cplusplus
is always 201703L or higher. This patch removes checks
for __cplusplus value that always succeed.
Change-Id: I4b830683ecefab8f913d8b09604086d53209d2e3
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
QMetaType does. QVariant should do the same.
Pick-to: 6.2
Change-Id: I3419276b78b3b5ce8bd144dee92685195797d568
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Daniel Nicoletti <daniel.nicoletti@kdab.com>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Match the checks in the constructor test that are similar.
Change-Id: Ifb62af09e31aac339f001f44bc30789330c85be6
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Before this change, the QMetaType for T const* where T is derived from
QObject would not store the static QMetaObject of T. This commit changes
this. As a consequence, the metatype system can now convert between
const and non-const pointers to QObject. Note that this allows casting
const away; but so does C++ with const_cast.
In addition, a new flag, QMetaType::IsImmutable is introduced, and used
to tag the metatypes of pointer to const types. This allows code to
discern between pointers to mutable and const QObjects, which is
relevant for the QML engine.
Task-number: QTBUG-82354
Change-Id: I3e4e4f39f565bd99a65e161528ce5304df73d6d6
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
In Qt 5, QVariant::fromValue<T> would not compile unless
Q_DECLARE_METATYPE(T) was used, and Q_DECLARE_METATYPE(T) would lead to
a compile error if T were not copy constructible.
In Qt 6, we do not require Q_DECLARE_METATYPE before using fromValue,
and QMetaType itself works with non-copy constructible types just fine.
However, QVariant still requires it, thus we need to now enforce this in
fromValue itself.
Change-Id: Ib6964a438d8c46033dd3a037b9d871de2b42e175
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
